The Key Technology Of Cultivation For The Container Seedling Of Carya Illinoinensis

Carya illinoensis combines nut,timber and ornamental values.Since the regulation by the properties of the land and the national timber strategy policy,the multiple useful forest seedlings such as nut and wood have gradually been planted in the hills and mountains area.Then the high-quality container seedlings are needed.Based on comparing and analyzing the effects of plant growth regulators,seedling substrates and container specifications on the growth,biomass accumulation and distribution,leaf photosynthetic characteristics and root growth of seedlings of C.illinoensis,this research provided technical guidance for the cultivation of the seedlings.The main results were as follows:（1）The simultaneous use of the root systems and leaves of C.illinoensis seedlings with different concentrations of naphthalene acetic acid and paclobutrazol had a significant impact on the growth of the seedlings.Naphthaleneacetic Acid（NAA）with 100 mg/L+Paclobutrazol(PP₃₃₃)with 200 mg/L had the best effect on promoting root growth.After30 days of using this treatment,the average length of the main root was 40.75±1.94 cm,the average underground root biomass accumulation was 13.19±0.51g,and the root-crown ratio was 2.07±0.13,which was suitable for cultivating the seedlings.（2）The cultivation material inside the containers had a significant effect on the growth,photosynthetic physiology and nutrient absorption of the seedlings.Compared to a single matrix and the formulated matrix,the formula material could provide more nutrients to the seedlings and promote the nutrient growth of the seedlings.The average diameter of the seedlings cultivated in matrix 5（peat soil:base yellow-brown loam soil:grass and wood ash:sawdust=4:2:2:2）was 5.05±0.73 mm,the average seedling height was 43.2±0.62cm,the biomass accumulation was 21.7 g,the average net photosynthetic rate of leaves were 12.74±0.46μmol/m²/s,and the average contents of leaf TN,TP and TK was 0.44±0.03 mg/g,1.67±0.15 mg/g,and 0.116±0.003 mg/g,respectively.The matrix 5 had the best effect on seedlings among these 6 matrices.（3）In order to balance the trade-off between seedling cost and seedling growth,the results showed that the size of the container had a significant impact on the growth of the seedlings.The root collar diameter,length of main root and its diameter ratio of seedlings raised in large size seedling containers were better than those in medium and small size containers.Considering the growth status and economic input of seedlings,non-woven fabric bag in 25 cm×30 cm size was the best container for cultivating seedlings,which was the most suitable container for the growth of 1～2 years old seedlings.In summary,the suitable technique conditions for container seedlings of C.illinoensis included the non-woven fabric container with the size of 25 cm×30 cm,the substrate with the ratio of peat soil,yellow-brown loam soil,grass and wood ash and sawdust equals4:2:2:2.Watering with 100 mg/L NAA on the basal roots,and spraying with 200 mg/L PP₃₃₃on the foliar surface at the seedling stage,respectively gave the best results.